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PubMed2002

The influence of human amniotic fluid on the potential of rabbit ear perichondrial flaps to form cartilage tissue.

Since several experimental and clinical studies demonstrated the chondrogenic potential of perichondrium, there has been great interest in examining factors that might promote neochondrogenesis from perichondrium. Human amniotic fluid contains hyaluronic acid, growth factors and extracellular macromolecules, and may, therefore, have a stimulating effect on cartilage regeneration. This experimental study investigated the effect of human amniotic fluid on cartilage regeneration from rabbit ear perichondrial flaps, using 96 ears of 48 New Zealand young rabbits. A perichondrial flap was elevated and a cartilage defect measuring 20 mm x 15 mm was created on the dorsum of each ear, then the perichondrial flap was sutured in place. The ears were divided into two groups according to the solution injected underneath the perichondrial flap. The right ears, which were injected with 0.2 ml human amniotic fluid, formed the experimental group, and the left ears, which were injected with 0.2 ml saline, formed the control group. Macroscopic and histological progression of neochondrogenesis were evaluated at 2, 4, 6 and 8 weeks after surgery. Macroscopically, the cartilage in the experimental group was generated quickly and had a similar appearance to the surrounding cartilage tissue, whereas in the control group minimal cartilage formation was observed at 4 weeks. Histologically, the neocartilage was significantly thicker in the experimental group than in the control group at 8 weeks (P < 0.05, Student's t -test). It can be concluded that human amniotic fluid enhances new cartilage formation from rabbit ear perichondrial flaps. The preventive effect of human amniotic fluid on scar formation and the rich content of growth factors and extracellular matrix precursors may play a role in this result.

Amniotic Fluid↗
PubMed2003

Prevalence of Mycoplasma bacteria in amniotic fluid at the time of genetic amniocentesis using the polymerase chain reaction.

OBJECTIVE: To use the polymerase chain reaction (PCR) to detect the presence of bacteria and Mycoplasma in amniotic fluid at the time of genetic amniocentesis and to assess their relationship to amniotic fluid interleukin-6 (IL-6) concentration and preterm delivery. STUDY DESIGN: A prospective study was performed on 78 asymptomatic pregnancies presenting for genetic amniocentesis. Amniotic fluid samples were analyzed by PCR for the detection of bacterial 16S ribosomal RNA, by PCR/enzyme-linked immunosorbent assay (ELISA) for Mycoplasma and by ELISA analysis for IL-6 concentration. RESULTS: All 78 samples were analyzed, and bacterial RNA was detected in 18% of them. However, no sample tested positive for Mycoplasma. The mean IL-6 concentration was 435 pg/mL. There was no difference in IL-6 levels or gestational age between bacteria-positive and -negative groups. CONCLUSION: Amniotic fluid may not be sterile in the midtrimester, yet the presence of bacteria, as detected by PCR, does not always result in an inflammatory response or adverse perinatal outcome.

Adult↗
PubMed1989

Complement activation and anaphylatoxin (C3a and C5a) formation in preeclampsia and by amniotic fluid.

The aim of this study was to determine whether the biologically active complement peptides C3a and C5a are formed in pregnancy and whether amniotic fluid can activate complement. C3a and C5a are formed when complement is activated. They increase smooth-muscle contraction, vascular permeability, and histamine release from mast cells and basophils. Thirty pregnant women were studied, 16 with uncomplicated and 14 with preeclamptic pregnancies. The plasma C3a and C5a concentrations before delivery were significantly higher in the preeclamptic than in the normal group. The concentrations returned to normal within 1 week. Plasma, serum, and amniotic fluid from 12 pregnant women (eight uncomplicated and four preeclamptic pregnancies) were drawn in connection with delivery. Amniotic fluid was incubated in fresh autologous serum at 37C for 15 minutes. A dose-dependent formation of C3a and C5a was registered with increasing amounts of amniotic fluid.

Adult↗
PubMed1987

Oxytocin levels in maternal and fetal plasma, amniotic fluid, and neonatal plasma and urine.

Oxytocin was measured in maternal and fetal plasma, amniotic fluid and neonatal plasma and urine using a specific radioimmunoassay, following extraction procedures with Florisil. Maternal oxytocin levels rose progressively with advancing gestation, but there were no significant differences between oxytocin levels around the onset of labor. No diurnal rhythm of oxytocin was evident in maternal plasma during the third trimester. Maternal and umbilical plasma oxytocin levels at spontaneous delivery were significantly higher than those at elective cesarean section. Maternal oxytocin levels in four cases of post-term delivery were lower than those during normal late pregnancy; all four cases experienced uterine inertia. All amniotic fluid samples had detectable oxytocin levels and there were no significant differences between oxytocin levels in the second trimester and those in the third trimester. Oxytocin levels in neonatal urine were higher than levels in amniotic fluid and lower than in the umbilical artery. Neonatal plasma oxytocin levels gradually decreased and oxytocin levels of 7-day-old infants were significantly lower than those in the umbilical artery, but higher than those in adults. In conclusion, it appears that maternal oxytocin levels may not be involved in triggering the onset of labor but may play a role in the maintenance and reinforcement of labor.

Adult↗
PubMed1994

Growth hormone, insulin-like growth factor-I and somatostatin in human fetus, newborn, mother plasma and amniotic fluid.

During pregnancy, organism development and its differentiation are stimulated and modulated by fetal and placental hormones. However the exact role played by all the different growth factors has not been explained yet. This study summarizes knowledge about secretion, regulation and role of GH, IGF-1 and SRIF during perinatal age. It also reports the results of researches into GH, IGF-1 and SRIF in amniotic fluid, in mothers and in newborns at delivery and at four days of age. Amniotic fluid GH levels proved significantly higher during middle pregnancy that at delivery (p < 0.001); a significant difference was also found between mean GH concentrations observed in amniotic fluid collected at delivery in preterm and full-term pregnancies. In amniotic fluid, significant reductions of SRIF and IGF-1 concentrations correspond to a sudden decrease of GH concentration during the last months of pregnancy. Fetal serum GH levels resulted higher than venous cordonal GH concentration at birth (p < 0.001). High levels of IGF-1 were found in the amniotic fluid and in the maternal plasma. These values were higher than those observed in cord blood during pregnancy or at delivery. Preterm and full-term newborns showed similar serum GH levels at birth and at the age of 4 days. Mean GH values in newborns, both at birth and at the age of 4 days, proved to be significantly higher than the values of their mothers (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Amniotic Fluid↗
PubMed1993

Elevated second-trimester amniotic fluid concentration of insulin-like growth factor binding protein-1 in fetal growth retardation.

OBJECTIVE: The aim was to study the levels of amniotic fluid and maternal serum insulin-like growth factor binding protein-1 levels at 15 to 16 weeks' gestation with regard to fetal growth in the third trimester. STUDY DESIGN: Amniotic fluid (n = 148) and maternal serum (n = 129) levels of insulin-like growth factor binding protein-1 were prospectively measured. RESULTS: Elevated amniotic fluid insulin-like growth factor binding protein-1 levels were related to fetal growth retardation. At a cutoff value of 3 multiples of the median a high-risk group comprising 16% of all pregnant women was identified. This group included 40% of all small-for-gestational age (birth weight < 10th percentile) and 55% of all very-small-for-gestational-age (birth weight < 5th percentile) infants. Maternal serum insulin-like growth factor binding protein-1 levels were not significantly elevated in these groups. CONCLUSION: In most cases of intrauterine growth retardation the disturbance may exist before the condition is detectable by ultrasonography. An elevated amniotic fluid insulin-like growth factor binding protein-1 level may be an early sign.

Adult↗
PubMed1994

Antenatal diagnosis of tetrahydrobiopterin deficiency by quantification of pterins in amniotic fluid and enzyme activity in fetal and extrafetal tissue.

Prenatal diagnosis of tetrahydrobiopterin (BH4) deficiency was undertaken by evaluating the pterin patterns in amniotic fluid and the specific enzyme activities in fetal or extrafetal tissues. This allowed the prenatal diagnosis in 19 pregnancies at risk. In 8 families with a child already affected by dihydropteridine reductase deficiency 4 fetuses were diagnosed as homozygotes and 4 as heterozygotes for the defect. In 11 families with a child affected by 6-pyruvoyl tetrahydropterin synthase deficiency 4 fetuses were homozygous, 4 heterozygous and 3 normal. This study also advanced our knowledge of tetrahydrobiopterin metabolism during fetal development. The key enzymes involved in the biosynthesis of BH4 are expressed early and allow the fetus to be autotrophous for its cofactor requirement. In a twin pregnancy, both fetuses were diagnosed to be heterozygotes for dihydropteridine reductase deficiency and primapterin (7-biopterin) in amniotic fluid was increased. This indicates that pterin-4 alpha-carbinolamine dehydratase activity seems to be differently expressed during fetal life. As a consequence, pterins detected in amniotic fluid are of fetal origin and 6- and 7-substituted pterins can be present in amniotic fluid in higher proportions when compared with other body fluids.

Alcohol Oxidoreductases↗
PubMed1993

Interleukin 8 concentrations in amniotic fluid and peripheral venous plasma during human pregnancy and parturition.

To establish the gestational and labour-associated changes in interleukin 8 (IL-8) release, we have determined the concentration of this cytokine in maternal peripheral plasma and amniotic fluid from 15 weeks of gestation to term and in association with spontaneous-onset labour at term and preterm. No statistically significant changes in peripheral plasma IL-8 concentration were observed during pregnancy or in association with labour onset (mean concentration 56.5 +/- 14.5 ng/l, N = 64). The IL-8 concentrations in amniotic fluid were up to 50-fold greater than those observed in peripheral plasma (p < 0.05) and increased significantly (p < 0.05) during pregnancy. At term, but before the onset of labour, amniotic fluid concentrations of IL-8 averaged 969.2 +/- 553.5 ng/l (N = 12). In association with labour at term, IL-8 concentrations increased to 3895.8 +/- 1414.4 ng/l (N = 6, p < 0.03). The concentration of IL-8 in amniotic fluid obtained from women in preterm labour averaged 1854.7 +/- 1352.6 ng/l (N = 6) but was not statistically different from the concentration of IL-8 in amniotic fluid obtained from gestational aged-matched non-labouring controls. Although the precise role of intrauterine IL-8 at the time of parturition awaits elucidation, these data support the concept that this cytokine may be involved in the biochemical events associated with the onset and/or propagation of normal labour in the human.

Amniotic Fluid↗
PubMed1990

Chediak-Higashi syndrome in the cat: prenatal diagnosis by evaluation of amniotic fluid cells.

Chediak-Higashi syndrome (CHS) is an autosomal recessive disease in humans, cats, and 8 other species. The homology of CHS in humans and cats has been demonstrated. Since human CHS is a progressive, serious, and eventually fatal disease, a method for prenatal diagnosis would be desirable. This study was designed to determine whether CHS could be diagnosed prenatally by examination of amniotic fluid cells. The amniotic fluid samples were obtained from CHS and control cat fetuses on the 45th day of gestation and cultures of cells were established. Because the underlying enzyme deficiency in CHS has not been identified, it was necessary to use a secondary manifestation of the syndrome in these studies. The secondary manifestation used was the characteristic enlargement of lysosomes associated with the disease. The lysosomes of these cells were stained by acid phosphatase histochemistry and the diameter of the largest lysosome in each cell was measured by light microscopy with a calibrated ocular micrometer. The diameters of the largest lysosomes in cells of normal fetuses ranged from 0.5 to 7.0 micron (means ranged from 0.9 to 1.8 micron), whereas the diameter of the largest lysosomes in the cells of CHS fetuses ranged from 0.5 to 30 microns (means ranged from 6.4 to 12.8 microns). The approximate t-test for independent samples with unequal variances disclosed that the largest acid phosphatase-positive lysosomes in amniotic fluid cells of CHS cat fetuses were significantly larger than the lysosomes in the cells of normal cat fetuses (P less than 0.0001). This information should, by extrapolation, provide the basis for the prenatal diagnosis of human CHS by amniocentesis.

Acid Phosphatase↗
PubMed2006

The effects of maternal position on the amniotic fluid index.

OBJECTIVE: We investigated the influence of maternal positioning on the measurement of the amniotic fluid index (AFI) in third-trimester pregnancies. We wanted to determine whether a change in the position of the women, from supine-flat to supine-elevated, would influence the measurement of the AFI. METHODS: Each patient had AFI measurements obtained in both positions by the same investigator. RESULTS: We determined the values of the amniotic fluid index to be consistent in both positions for pregnancies with normal AFI measurements. CONCLUSIONS: Measurements of the amniotic fluid did not appear to be influenced by maternal position in the third trimester when the AFI was in the normal range.

Amniotic Fluid↗
PubMed1986

Amniotic fluid retinol concentrations in late pregnancy.

The concentrations of retinol (vitamin A) were measured in 36 samples of human amniotic fluid obtained near term. Mothers with normal pregnancy had higher amniotic fluid retinol levels than patients with diabetes or toxemia. The results indicate that some maternal complications during pregnancy affect the transport of retinol into amniotic fluid, possibly due to reductions in the uteroplacental blood flow.

Amniotic Fluid↗
PubMedDate not supplied

Amniotic fluid embolism with haemostasis complications: primary fibrinogenolysis or disseminated intravascular coagulation?

Amniotic fluid embolism (AFE) is characterized by the passage of amniotic fluid (AF) into the maternal circulation during or just after childbirth. AFE is a rare disorder occurring in 1/8,000 to 1/80,000 deliveries but with a maternal morbidity ranging from 26% in a recent report to 86% in earlier ones. In patients who survive, AFE may affect coagulation resulting in severe bleeding. While disseminated intravascular coagulation (DIC) is usually seen in such cases, we reported a case of AFE in which the hemostatic abnormalities were compatible with primary fibrinogenolysis rather than with DIC.

Adult↗
PubMed1990

The relationship between maternal serum and amniotic fluid alpha-fetoprotein in women undergoing early amniocentesis.

alpha-Fetoprotein levels were measured on 148 paired samples from the maternal serum and amniotic fluid in women greater than or equal to age 35, who were undergoing early amniocentesis (12 to 14 weeks) for chromosomal analysis. These 148 women were white, weighed less than 200 pounds, had no serious medical problems, and did not have a fetal abnormality detected by ultrasonography or karyotype analysis. There was a significant rise in the maternal serum alpha-fetoprotein concentration from 12 to 14 weeks' gestation. Amniotic fluid alpha-fetoprotein peaked at 13 weeks and then significantly declined by 14 weeks' gestation. Similar to reports from normal pregnancies at 16 and 17 weeks, we found no correlation between the maternal serum and amniotic fluid alpha-fetoprotein levels between 12 and 14 weeks. Amniotic fluid alpha-fetoprotein levels cannot be predicted by levels in the maternal serum in pregnancies between 12 and 14 weeks' gestation.

Adult↗
PubMed1983

Fetal pulmonary maturity: relationship between optical density (650 nm) to the lecithin/sphingomyelin ratio and phosphatidylglycerol in amniotic fluid.

An optical density value greater than or equal to 0.15 at A650 n m of amniotic fluid obtained through transabdominal amniocentesis from a high risk obstetrical population, which excluded diabetes mellitus, isoimmunization, and amniotic fluid infection, correlated 98.6% with a mature lecithin to sphingomyelin ratio (L/S) greater than or equal to 2.0% and 41.6% with the presence of phosphatidylglycerol (PG). The corresponding false positive rates were 1.4% and 16.8%, respectively. In 30 infants delivered within 48 h of testing, A650 n m greater than or equal to 0.15 correlated 100% with absence of respiratory distress syndrome. A650 n m is not recommended for Rhesus immunized gestations, diabetic pregnancies and amniotic fluid infection due to a high false positive rate with A650 nm compared to L/S and PG.

Amniotic Fluid↗
PubMed1976

Changes in human amniotic fluid fibrinolytic inhibitor levels during pregnancy.

The amniotic fluid (AF) when incubated with the patient's own plasma diminishes the lytic activity of the plasma. It is suggested that this inhibition is due to the presence of fibrinolytic inhibitors in the AF. The inhibitors rate increases as pregnancy advances. Evaluating these inhibitors in a group of 65 women before and after the 38th week of pregnancy, a higher rate of fibrinolytic inhibitors is found after the 38th week. The said differences are statistically significant. For the moment it does not seem that the increasing of the inhibitors in the last part of pregnancy might be used as a fetal maturity test.

Amniotic Fluid↗
PubMed1981

Management of preterm premature rupture of membranes: assessing amniotic fluid in the vagina for phosphatidylglycerol.

This prospective study evaluates the clinical practicality of assessing free amniotic fluid in instances of premature rupture of the membranes (PROM) before term. The presence of phosphatidylglycerol (PG) provided evidence of fetal pulmonary maturity. Daily aspirations of vaginally pooled amniotic fluid were performed on 55 consecutive patients with preterm PROM and met with a success rate of 80% (79 of 99 attempts). Respiratory distress syndrome (RDS) occurred in none of 28 neonates in whom PG was present prior to delivery, and in four of 19 in whom PG was absent. Evidence of surfactant maturation at the time of initial sampling was noticed in 24% of fetuses at 28 to 34 weeks' gestation. Those who initially lacked PG showed an acceleration of its appearance in the aminotic fluid with time, and almost all required a minimum of 48 to 72 hours. Sampling free amniotic fluid for PG is reliable, noninvasive procedure which can be usefully applied to the management of preterm PROm.

Adult↗
PubMed1993

Interleukin-6 levels in amniotic fluid in normal and abnormal pregnancies: preeclampsia, small-for-gestational-age fetus, and premature labor.

OBJECTIVE: Our purpose was to determine if abnormal amniotic fluid interleukin-6 levels correlate with pregnancies complicated by preeclampsia, small-for-gestational-age fetus, and premature labor. STUDY DESIGN: A case control study design was used to compare third-trimester amniotic fluid interleukin-6 levels from women with normal pregnancies (n = 25) and pregnancies complicated by preeclampsia (n = 15), small-for-gestational-age perinates (n = 8), and premature labor (n = 29). RESULTS: Amniotic fluid interleukin-6 levels in women with preeclampsia and small-for-gestational-age perinates were less than in controls (p < 0.01). Interleukin-6 levels in women with preterm labor refractory to tocolysis were higher than those in women with preterm labor responsive to tocolysis (p < 0.01). CONCLUSIONS: Interleukin-6 is normally present in amniotic fluid. In the third trimester of pregnancy low levels correlate with small-for-gestational-age fetuses and preeclampsia, whereas elevated levels correlate with preterm labor and delivery.

Amniotic Fluid↗